Hemostatic clipping devices and methods

ABSTRACT

A tissue clipping apparatus, comprises a flexible, elongate member, a proximal end of which remains external to the body accessible to a user while a distal end of the flexible member is inserted into the body to a location adjacent to target tissue to be clipped and a control wire extending through the flexible member in combination with a capsule releasably coupled to a distal end of the flexible member and a clip a proximal portion of which is received within the capsule. A joint releasably coupling the clip to the control wire, includes a yoke extending around a proximal end of the clip and a frangible link which fails when subject to a predetermined force to separate the clip from the control wire.

PRIORITY CLAIM

The present application is a Continuation of U.S. patent applicationSer. No. 12/485,542 filed on Jun. 16, 2009, now U.S. Pat. No. 8,663,247;which claims priority to U.S. Provisional Application Ser. No.61/074,094 filed on Jun. 19, 2008. The disclosure of the abovepatent(s)/application(s) is incorporated herein by reference.

BACKGROUND

Pathologies of the gastro-intestinal (“GI”) system, the biliary tree,the vascular system and other body lumens and hollow organs are commonlytreated through endoscopic procedures, many of which require activeand/or prophylactic hemostasis to reduce internal bleeding. Tools fordeploying hemostatic clips via endoscopes are often used to stopinternal bleeding by clamping together the edges of wounds or incisions.

In the simplest form, these clips grasp tissue surrounding a wound,bringing edges of the wound together to allow natural healing processesto close the wound. Specialized endoscopic clipping devices are used todeliver the clips to desired locations within the body and to positionand deploy the clips at the desired locations after which the clipdelivery device is withdrawn, leaving the clip within the body.

Endoscopic hemostatic clipping devices are generally designed to reachtissues deep within the body (e.g., within the GI tract, the pulmonarysystem, the vascular system or other lumens and ducts) via a workinglumen of an endoscope. Thus, the dimensions of the clipping device arelimited by the dimensions of the working channels of endoscopes withwhich they are to be employed.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a tissue clippingapparatus comprising a flexible, elongate member, a proximal end ofwhich remains external to the body accessible to a user while a distalend of the flexible member is inserted into the body to a locationadjacent to target tissue to be clipped. A control wire extendingthrough the flexible member in combination with a capsule is releasablycoupled to a distal end of the flexible member and a clip, a proximalportion of the clip being received within the capsule. A jointreleasably coupling the clip to the control wire includes a yokeextending around a proximal end of the clip and a frangible link whichfails when subject to a predetermined tension to separate the clip fromthe control wire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a single piece hemostatic clipaccording to an embodiment of the present invention;

FIG. 2 is a perspective view a single piece hemostatic clip according toan embodiment of the present invention;

FIG. 3 is a cross-sectional view of a distal tip of a retainer for theclip of FIG. 1;

FIG. 4 is a perspective view of a retainer for the clip of FIG. 1;

FIG. 5 is a perspective view of a single piece hemostatic clip accordingto a second embodiment of the present invention;

FIG. 6 is a perspective view of a clevis according to a secondembodiment of the present invention;

FIG. 7 is a perspective view of a single piece hemostatic clip accordingto a second embodiment of the present invention;

FIG. 8 is a cross-sectional view of a shear pin according to a secondexemplary embodiment of the present invention;

FIG. 9 is a perspective view of a clip according to a third exemplaryembodiment of the present invention;

FIG. 10 is a partial cross sectional view of a clip according to a thirdexemplary embodiment of the present invention;

FIG. 11 is a perspective view of a clip according to a fourth exemplaryembodiment of the present invention;

FIG. 12 is a perspective view of a deployed clip according to a fourthexemplary embodiment of the present invention;

FIG. 13 is a perspective view of a wire lock mechanism according to anembodiment of the present invention;

FIG. 14 is a second perspective view of the wire lock mechanismaccording to an embodiment of the present invention;

FIG. 15 is a cross sectional view of the wire lock mechanism accordingto an embodiment of the present invention;

FIG. 16a is a perspective view of the wire lock mechanism according tothe present invention;

FIG. 16b is a close-up view of the wire lock mechanism according to thepresent invention; and

FIG. 16c is a perspective view of a crushed wire lock mechanismaccording to the present invention.

DETAILED DESCRIPTION

According to the embodiments of the present invention, a hemostaticclipping device is provided that is relatively simple to manufacture anduse. Exemplary embodiments of the clipping device improve on thedeployment mechanism for both single and two piece hemostatic clips aswell as on the mechanism for tip-catheter separation. The embodimentsalso provide protection of the working channel of the endoscope fromsharp edges of the clip deployment device. Examples of hemostatic clipscurrently employed in the field include clips such as those disclosed inU.S. Patent Application No. 60/915,806 entitled “Single Stage HemostasisClipping Device” filed on May 3, 2007 by Cohen et al. (hereinafter the'806 application), the entire disclosure of which is incorporated hereinby reference.

As shown in FIGS. 1-4, a clipping device 100 according to an exemplaryembodiment of the invention deploys from within a capsule 110 a singlepiece hemostatic clip 102 including a pair of tissue gripping arms 104to clamp tissue to, for example, clamp a wound closed to stop bleeding.The hemostatic clip 102 is formed of a biocompatible material includingmetals such as stainless steel and Nitinol, polymers, biologicalmaterials and the like, as would be understood by those skilled in theart. During an initial insertion configuration, the clip 102 iscontained within the capsule 110, constraining the arms 104 in a closedconfiguration with distal ends of the arms 104 in proximity to oneanother against a bias of the arms 104 which urges them apart into theopen, tissue receiving configuration shown in FIG. 1. Specifically, aproximal portion of the clip 102 is housed within the capsule 110 alongwith proximal and intermediate portions of the arms 104, wherein contactbetween the inner walls of the capsule 110 and the arms 104 draws thearms 104 closed against one another. A proximal portion of the capsule110 is connected to a flexible member 130, which is formed, for example,as an elongated tubular structure extending to a proximal portion of thedevice 100 which remains outside the body at all times. The flexiblemember 130 may be formed as a coil or, alternatively, as any othersuitable hollow, flexible structure. In an exemplary embodiment, theflexible member 130 is made of a suitably thin material which transmitsto the distal end rotation applied in either direction to the proximalportion without substantially winding up. Specifically, rotation of theproximal portion of the device 100 about the longitudinal axis istransmitted along the flexible member 130 to the capsule 110 to positionthe clip 102 in an optimum orientation relative to a portion of tissueto be gripped thereby. A control wire 132 is slidably received withinthe flexible member 130 with a distal end thereof received within thecapsule 110, as will be described in greater detail below. A proximalportion of the control wire 132 is connected to an actuator (not shown)on the proximal portion of the device 100 where it remains accessible toa user throughout the procedure.

A proximal portion of the clip 102 may be formed in a relativelyhourglass shape with a bulbed proximal end 111. The bulbed shape of theproximal end 111 can maximize a clip-opening angle of the clip 102, asthose skilled in the art will understand, while the hourglass shapeforms a space 136 within the proximal end 111 for receiving therein ayoke post 112 of a deployment mechanism. The yoke post 112 may becoupled to the control wire 132 via a yoke 114 and a clevis 116 so thatmovement of the control wire 132 proximally and distally through theflexible member 130 facilitates contact between the yoke post 112 andthe proximal end 111 and thus moves the clip 102 proximally and distallyrelative to the capsule 110. As would be understood by those skilled inthe art, the shape of the yoke post 112 is not important so long as theyoke post 112 is strong enough to transmit the desired proximal anddistal forces from the control wire 132 to the clip 102. Thus, the yokepost 112 may be formed in various geometries including, for example,rectangular, round or oval, etc. As would be understood by those skilledin the art, a proximal portion of the yoke 114 can be coupled to theclevis 116 via a shear pin 118 which is designed to fail when subject toa predetermined force, such as a tension exerted thereto via the controlwire 132. As shown in FIGS. 2 and 3, the shear pin 118 may be formed,for example, as a substantially cylindrical pin extending throughopenings in the yoke 114 and the clevis 116 with ends thereof, in oneembodiment, having a conical radius aiding in centering the clip 102 inthe capsule 110. However, any other suitable shapes of the yoke 114 maybe applied as well. In an alternate embodiment, the shear pin 118 may becoupled to one or both of the yoke 114 and the clevis 116 via aninterference fit. The yoke 114 may include lateral walls which extendover sides of the clevis so that the shear pin 118 may pass on a linethrough both the yoke 114 and the clevis 116, as can be seen in theembodiment of FIG. 3. Each lateral wall of the yoke 114 may furthercomprise a centering boss 120 formed as a tabbed protrusion projectingradially outward therefrom. The centering boss 120 can be formed with aradius consistent with the inner diameter of the capsule 110 to centerthe clip 102 therein. A proximal end of the clevis 116 can be attachedto a distal end of the control wire 132. In this embodiment, the distalend of the control wire includes a ball joint 133 which is received in acorrespondingly sized and shaped recess of the clevis 116, coupling theclevis 116 to the control wire 132. Those skilled in the art willrecognize that any number of attachment arrangements may be used to bondthe control wire 132 to the clevis 116 so long as the attachment iscapable of transmitting the desired force, such as tension from thecontrol wire 132 to the clevis 116 and, consequently, to the yoke 112and the clip 102. Thus, actuation of the control wire 132 distally andproximally can open and close the clip according as will be described inmore detail below.

The clip 102 of the present invention may be opened and closed aplurality of times during a procedure so long as a proximal pull forceexerted on the control wire 132 does not exceed a predeterminedthreshold which is designed to cause the shear pin 118 to fail, thuslocking the clip 102 closed, as will be described in more detail below.Specifically, a user may open and close the clip 102 a plurality oftimes to properly situate the clip 102 over target tissue before lockingthe clip 102 in place. When a desired placement area has been reached,and it is desired to lock the clip 102 in place, the user may draw thecontrol wire 132 proximally to draw the clip 102 into the capsule 110.Alternatively, the capsule 110 may be advanced distally to provide theforce necessary to draw the clip 102 thereinto. The arms 104 graduallyincrease in width from a narrow proximal end to increased widthshoulders 104 b at a distal end so that, as the clip 102 is drawnproximally into the capsule 110, a point is reached at which the clip102 is closed, with distal ends of the arms 104 coming together to griptissue and the shoulders 104 b engaging the distal end of the capsule110 to prevent the clip 102 from being drawn further into the capsule110. At this point, an additional pull force exerted on the control wire132 increases the tension on the shear pin 118 until a failure level isreached. When this happens, the clevis 116 is separated from the yoke112 and the clip 102 is locked in the closed configuration over anytissue gripped thereby. The clip 102 may employ a locking means known inthe art. The shear pin 118 is made of a material such as a polymer or ametal such as tantalum, gold or silver, wherein the release force of thematerial is approximately 26.69-66.72 N. Alternatively, the releaseforce may vary from 20-80 N. Thus, the clevis 116 and yoke 114 can beformed to have a strength greater than that of the shear pin 118. Theseitems may be formed, for example, of Stainless Steel or a high strengthpolymer or thermoset. The fractured shear pin 118 is adapted to remainhoused within the capsule 110, wherein a construction thereof ensuresthat fractured pieces thereof do not include sharp edges. In thismanner, smaller fractured portions thereof pose no potential harm to apatient even if they escape the capsule 110.

As described in more detail in the '806 application, as the freed clevis116 is pulled proximally, it engages a distal face of a bushing support135, driving the bushing support 135 proximally into a bushing 134 atthe distal end of the flexible member 130. When received within theproximal end of the capsule 110, the bushing support 135 engages atleast one tab (not shown) of the bushing 134 urging the tab radiallyoutward into engagement with corresponding windows (not shown) of thecapsule 110. The tabs of the bushing are biased toward a radially inwardposition out of engagement with the windows of the capsule 110 so that,when the bushing support 135 is dislodged from the proximal end of thecapsule 110, the tabs of the bushing 134 are freed to disengage thewindows of the capsule and the capsule 110 is permanently separated fromthe bushing 134 and the flexible member 130, leaving the clip 102 lockedon the gripped tissue. The flexible member 130 may then be withdrawnfrom the body.

In an alternate embodiment, instead of the bushing support 135, thecapsule 110 may be maintained in engagement with the bushing 134 by aretainer 140 formed at the distal end of the bushing 134. The retainer140 may include tabs 146 which engage corresponding windows (not shown)in the capsule 110 (or, alternatively, by a friction fit). The retainer140 may comprise an opening 142 sized to slidably receive the controlwire 132 therein with a slot 143 allowing the retainer 140 to be slid inplace over the wire 132. The slot 143 is sized to allow the retainer 140to be clipped onto the control wire 132, thus obviating the need tothread the control wire 132 through the retainer 140. The retainer 140may further comprise two spring arms 144, each of which may include atab 146 biased to engage the corresponding window of the capsule 110.Then, when the shear pin 118 fails and the clevis 116 is drawnproximally as described above, the clevis 116 can drive the retainer 140into the bushing 134, drawing the tabs 146 out of engagement with thecapsule 110 and freeing the capsule 110 from the flexible member 130 ina manner similar to that described earlier. The flexible member 130 maythen be withdrawn from the body. In one embodiment, the retainer 140 iscomposed of a metal that can be tempered, such as 17-7 Stainless Steel.However, it is noted that the retainer 140 may be made of numerousbiocompatible materials including biocompatible metals and formablepolymers without deviating from the spirit and scope of the presentinvention.

As shown in FIGS. 5-8, a clip 200 according to a further embodiment ofthe invention, comprises a relatively hourglass-shaped proximal portionsized to engage a clevis 216 in a capsule 210 in a manner substantiallysimilar to that described above in regard to the device 100. However, inthis embodiment, the yoke and clevis have been replaced by a unitaryclevis 216 with arms 226 of the clevis 216 extending around the proximalend of the clip 200 so that a shear pin 218 received through openings228 of the clevis 216 extends into the hourglass-shaped proximal portionof the clip 200 in a manner similar to the yoke post 112 of the device100. The clip 200 may be coupled to a control wire 232 in a mannersimilar to that described for the device 100. Furthermore, theconnection between a flexible member 230 and the capsule 210 and themechanism for separating the capsule 210 from the flexible member 230may also be substantially similar to that described for the device 100.

The capsule 210 may be formed with clip retaining tabs 250 at a proximalportion thereof to hold the clip 200 in place within the capsule 210after deployment, thus locking the clip 200 in the closed configuration.Specifically, during deployment, the clip 200 is retracted proximally bya predetermined distance into the capsule 210, drawing thehourglass-shaped proximal portion of the clip 200 proximally past aproximal end of the tabs 250 and a decreased thickness portion 252 ofthe clip 200 distally of the hourglass-shaped proximal portion, adjacentto the tabs 250. This movement permits the tabs 250 to spring radiallyinward so that contact between the proximal ends of the tabs 250 and thehourglass-shaped proximal portion of the clip 200 locks the clip 200 inthe capsule 210 and prevents the clip 200 from re-opening. Furthermore,although a holding force applied by the clip retaining tabs 250 issubstantial enough to retain the clip 200 therein after deployment, itis preferably selected so that a distal force, such as a compressionforce applied to the control wire 232 may move the hourglass-shapedproximal portion distally past the tabs 250 enabling a user to reopenthe clip (e.g., for repositioning) at any time before the control wire232 is separated from the clevis 216.

As described above, arms 204 of the clip 200 are provided with shoulders204 b defining an increased thickness portion 204 a which prevent theclip 200 from being pulled into the capsule 210 beyond a predeterminedlength. Thus, when the clip 200 has been drawn into the capsule 210 bythis distance, additional pulling force applied to the control wireincreases a tension thereon until the fail level of the shear pin 218 isreached as described above. As shown in FIG. 8, the shear pin 218 may,for example, be provided with one or more stress concentrators 258formed as grooves formed along the outer diameter thereof, the stressconcentrators 258 defining a weaker point along the length of the shearpin 218. Those skilled in the art will understand that the size andnumber of these stress concentrators may be varied to obtain any desiredfail level of the shear pin 218.

As shown in FIGS. 9 and 10, a clip 300 according to another exemplaryembodiment of the invention can be releasably attached at a proximal endto a shell 360. The shell 360 may comprise proximal and distal halves362, 364, respectively, releasably attached to one another. A proximalend of the proximal half 362 can be attached to a control wire 332. Theproximal half 362 may be formed as two complementary pieces which areassembled over the distal end of the control wire 332. For example, afirst one of the pieces of the proximal half 362 may include one or moremale posts 368, while the other piece includes a corresponding set offemale holes 370 which aid in aligning the pieces with one another andbonding the pieces together (e.g., via adhesive) to form the proximalhalf 362. Similarly, the distal half 364 may be formed as two pieceswhich are assembled over the proximal end of the clip 300 with a similarset of complementary male posts 368 and female holes 370 to align thepieces when assembled (e.g., via adhesive) as the distal half 364. Thoseskilled in the art will understand that the pieces of the proximal anddistal halves 362, 364, respectively, may be formed by, for example,injection molding. Specifically, each of the proximal half 362 anddistal half 364 in this embodiment can be formed from a pair ofcomplementary semi-cylindrical pieces, attached to one another using themale posts 368 and female holes 370 as references. Furthermore, the maleposts 368 and female holes 370 may serve as energy directors forultrasonic welding, as those skilled in the art will understand.

The clip 300 may comprise two arms 304, each comprising a proximalportion extending radially outward and contained within a capsule 360,as shown in FIGS. 9 and 10. It is noted that although exemplaryembodiments of the present invention are disclosed as having two arms,any plurality of arms may be employed without deviating from the spiritand scope of the present invention. The clip 300 is further providedwith shoulders (not shown) which prevent the clip 300 from beingretracted into a capsule 360 beyond a predetermined distance asdescribed above in regard to the embodiments of FIGS. 1-8. A largecavity 307 is formed in the proximal end of the distal half 364 while acorresponding cavity 309 is formed in the distal end of the proximalhalf 362. The cavities 307, 309 receive proximal ends of the arms 304and constrain them to remain therein against a bias which urges theproximal ends of the arms 304 and tabs 305 formed thereby radiallyoutward.

Movement of the clip 300 is controlled by the control wire 332, whichextends through a flexible member 330 in the same manner described aboveout of the body to a proximal portion accessible to a user. A distal endof the control wire 332 may include an increased diameter portion suchas a sphere or cylinder is received within a correspondingly sized andshaped recess 372 at the end of a lumen in the proximal half 362 sizedto receive the distal portion of the control wire 332. Thus, theproximal half 362 can be coupled to the control wire 332 for movementproximally and distally therewith. A center post 318, which may extendproximally from a proximal end of the distal half 364, may include anincreased diameter portion 319 at a proximal end thereof. The proximalend of the post 318 may be coupled to side walls of the cavity 307 tobind the center post 318 to the distal half 364. The increased diameterportion 319 may be inserted into the recess 372 before the pieces of theproximal half 362 are bonded to one another in the same manner as thedistal end of the control wire 332. Thus, the post 318 can bind theproximal and distal halves 362, 364 to one another The recess 372 mayalso be sized to receive the distal end of the control wire 332 and theproximal end of the center post 318 with a substantial friction fit toprevent unwanted movement of the respective elements therein. Thoseskilled in the art will recognize that the control wire 332 and the post318 may be coupled to the proximal half 364 in any number of ways (e.g.,with separate recesses 372) including, but not limited to, welding,bonding, melting, etc.

During insertion, the clip 300 can be partially retracted into the shell360, causing the arms 304 to approach one another. Upon reaching atarget tissue site, a distal compressive force may be applied to acontrol wire 332, which translates the force to the center post 318, theforce being further translated to the distal half 364 of the shell 360,thereby pushing the clip 300 out of the shell and causing the arms 304to expand radially away from one another. When target tissue is receivedbetween the arms 304, the control wire 332 can be withdrawn proximallywhile maintaining the flexible member 330 and the capsule 360substantially immobile so that the clip 300 is retracted into the shell360 drawing the arms 304 toward one another. After the shoulders (notshown) have engaged the capsule 360 to prevent further withdrawal of theclip 300 thereinto, additional proximally directed force applied to thecontrol wire 332 increases tension on the control wire 332 and,consequently, on the post 318 until a failure level of the post 318 isexceeded. In one embodiment, the center post 318 is composed of amaterial similar to that of the shear pin 118 formed to fail atapproximately 26.69-66.72 N, as those skilled in the art willUnderstand. Alternatively, the center post 318 may be formed of anothersuitable material and/or geometry. When the post 318 fails, the proximaland distal halves 362, 364 can be separated from one another, and thetabs 305 which are no longer constrained by the walls of the cavity 309of the proximal half 362 can spring outward and engage correspondingfeatures of the capsule 360 (e.g., windows 363) to lock the clip closedand keep it in position within the capsule 360.

As shown in FIGS. 11 and 12, a clip 400 according to another exemplaryembodiment of the invention may include arms 404 residing in a capsule410. The arms 404 bend along a curve to bias the proximal and distalends thereof radially away from one another in a manner similar to thatof the embodiment of FIGS. 9 and 10. Curves of the proximal portions ofthe arms 404 may form a pocket 408 while the distal ends of the arms 404are formed in a manner substantially similar to that of the previouslydescribed embodiments. Proximal ends of the arms 404 may containopenings 406 through which a wire loop 418 may pass to couple the clip400 to a control wire 432. Those skilled in the art will recognize thatthe openings 406 may be formed as rounded openings with smoothed edgesto prevent unwanted trauma to the wire loop 418. In assembly, an end ofthe wire loop 418 can be passed through the openings 406 and the twoends of the wire loop 418 can be coupled to the distal end of thecontrol wire 432 using, for example, a wire mate 416 compressedthereover. For example, the wire mate 416 may comprise a section ofhypotube crushed over the wire loop 418. Alternatively, as would beunderstood by those skilled in the art, the wire mate 416 may be coupledto the wire loop 418 and the control wire 432 by staking, bonding,welding or any other known method. In the initial configuration, thewire loop 418 can be bound with a minimal clearance, thereby grippingthe proximal ends of the arms 404 tightly against one another againstthe bias of the arms 404 urging the proximal ends of the arms 404radially outward away from one another. In yet another embodiment (notshown), the control wire 432 may be formed as a single continuous wireextending from a proximal portion accessible to a user to a distalportion joined to the openings 406 with no mating portions at a distalportion thereof.

In the same manner described above, the control wire 432 may bemanipulated to position the clip 400 over a target portion of tissue. Asthe clip 400 is urged distally out of the capsule 410, the bias of thearms 404 moves the distal ends thereof away from one another to an opentissue receiving configuration. When the target tissue is receivedbetween the distal ends of the arms 404, the control wire 432 may bedrawn proximally to retract the clip 400 into the capsule 410 bringingthe distal ends of the arms 404 together to grip the tissuetherebetween. As the clip 400 enters the capsule 410, shoulders (notshown) of the arms 404 may contact the capsule 410 preventing furtherentry of the clip 400 into the capsule 410. Additional proximallydirected force applied to the control wire 432 after this pointincreases tension in the control wire 432 until the wire loop 418 fails,releasing the proximal ends of the arms 404 to spring radially outwardaway from one another allowing tabs 414 to engage windows 412 of thecapsule 410, locking the clip 400 closed and maintaining the clip 400 inthe capsule 410. The wire mate 416 now moves proximally to disengage thecapsule 410 from a flexible member (not shown) using a mechanism similarto any of those described in the previous embodiments.

As shown in FIGS. 13-16, any of the above embodiments may include alocking mechanism which will lock the control wire and any componentscoupled to the distal end thereof within the distal end of a bushing orflexible member as described above. This should prevent a user frommoving the severed control wire distally out of the distal end of theflexible member or bushing after the clip has been deployed to safeguardagainst injuries that may be caused by contact with the control wire orany components (e.g., proximal half 364) attached thereto.

Specifically, a closeable or crushable wire lock 500 is disclosed whichmay provide a streamlined system to more safely remove these componentsfrom the body. The closeable wire lock 500 is intended to preventpushing the sharp, sheared control wire into the anatomy for safetyreasons. The closeable wire lock 500 of the present invention may beused to forcibly separate the capsule 510 from a bushing 520 attached toa flexible member 530, the bushing 520 adapted to be separatable fromthe capsule 510 via a retainer or other mechanism as disclosed withreference to FIGS. 1-4. Specifically, the closeable wire lock 500 may beparticularly useful in cases where all other frangible links between thecapsule 510 and bushing 520 have been broken. Furthermore, the closeablewire lock 500 may be employed in any of the clip deployment mechanismsdisclosed herein.

With reference to FIGS. 13-16, a closeable wire lock 500 can be formedas a tube slidably receiving therein a control wire 532. A closeablesection of the lock 500 may include a series of hubs 502 coupled to oneanother by a series of struts 504 and separated from one another by aseries of openings 505. It is noted that although the present embodimentis disclosed with three hubs 502 and four struts 504, any number of hubs502 and struts 504 may be employed herein without deviating from thespirit and scope of the present invention. As in the embodimentsdescribed above, a control wire 532 may extend through the lock 500 to adistal end comprising, for example, a ball and socket joint within abushing 520. When the control wire 532 is separated from the clip andmoves proximally through the capsule, the ball 507 is adapted to enteran enlarged distal end 534 of the lock 500 formed, for example, as aseries of fins 536 separated from one another and bent slightly radiallyoutward. As the ball 507 moves proximally into the end 534 of the lock500, the fins 536 can grip the ball 507 preventing relative movementbetween the control wire 532 and the lock 500. Further proximallydirected force applied to the control wire 532 should draw the ball 507pushes the lock 500 proximally. A proximal end (not shown) of the lock500 can be immovably coupled to the flexible member 530 so that thisproximally directed force applied to the control wire 532 compresses thelock 500 causing the struts 504 to bend radially outward moving the hubs502 toward one another as the openings 505 are closed. When bentoutward, the struts 504 engage spaces between the coils of the flexiblemember 530 preventing relative movement between the lock 500 and theflexible member 530. Thus, the control wire 532 can be locked within thedistal end of the flexible member 530 and can not be advanced distallytherefrom to cause injury.

Clip and clip deployment mechanisms according to the present inventionmay be designed in a wide variety of sizes for applications such aswound closure, hemostasis, tissue bunching (e.g., to alter the size orshape of a hollow organ) or as fasteners to join tissue. Alternatively,clips according to the present invention may be used to anchor items totissue. Accordingly, although the present invention has been disclosedwith specific designs and applications, it is noted that a variety ofdesigns may be employed therein without deviating from the spirit andscope of the present invention. For example, a predisposed bias of aclip according to the present invention may be formed to lie at amidpoint between the fully open and fully closed configurations. In thismanner, the stress to which the clip is subjected in each of theseconfigurations is minimized, enabling the clip to be made more flexible.The specification and drawings are, therefore, to be regarded in anillustrative rather than a restrictive sense.

What is claimed is:
 1. A tissue clipping device, comprising: a flexible insertion member extending from a proximal end which, during use remains outside a body accessible to a user to a distal end which is inserted into the body through a naturally occurring body lumen; a clip including first and second clip arms; a capsule housing a portion of the clip therein; a control wire extending through the flexible insertion member from a proximal end to a distal end removably coupled to the clip by a joint at a proximal end of the clip, the control wire being reversibly operable to move the first and second clip arms between an open configuration in which distal ends of the first and second clip arms are separated from one another and a closed configuration in which the distal ends of the first and second clip arms are drawn together to grip tissue located therebetween; and an actuator coupled to the control wire and configured to move the first and second clip arms between the open and closed configurations, application of a predetermined force to the actuator applying a force to the control wire freeing the proximal end of the clip to move radially outward to engage an increased diameter portion of the capsule and disengage the control wire from the clip.
 2. The tissue clipping device of claim 1, wherein the capsule is configured to remain coupled to the clip when the control wire disengages from the clip.
 3. The tissue clipping device of claim 1, wherein the clip is a multi-piece clip.
 4. The tissue clipping device of claim 1, wherein a distal end of the control wire includes an enlargement configured to engage the clip.
 5. The tissue clipping device of claim 4, wherein the clip includes a recess having a shape corresponding to the shape of the enlargement of the control wire.
 6. The tissue clipping device of claim 1, wherein the capsule includes a cavity formed therein, the increased diameter portion extending along a wall of the cavity.
 7. The tissue clipping device of claim 6, wherein retraction of the clip into the capsule causes the proximal end of the clip to move into the increased diameter portion.
 8. The tissue clipping device of claim 1, wherein the capsule includes a proximal section and a distal section coupled to one another by a post extending from the distal section into a corresponding cavity formed in the proximal section.
 9. The tissue clipping device of claim 8, wherein the movement of the clip into the capsule causes the post to break, permitting the proximal end of the clip to expand into the increased diameter portion.
 10. The tissue clipping device of claim 1, wherein the first and second clip arms include increased width shoulders engaging a distal end of the capsule to prevent the first and second clips arms from being withdrawn into the capsule beyond a predetermined distance corresponding to a length of the shoulders.
 11. A tissue clipping device, comprising: a flexible insertion member extending from a proximal end which, during use remains outside a body accessible to a user to a distal end which is inserted into the body through a naturally occurring body lumen; a clip including first and second clip arms; a capsule housing a portion of the clip therein; and a control wire extending through the flexible insertion member from a proximal end to a distal end removably coupled to the clip by a joint at a proximal end of the clip, the control wire being reversibly operable to move the first and second clip arms between an open configuration in which distal ends of the first and second clip arms are separated from one another and a closed configuration in which the distal ends of the first and second clip arms are drawn together to grip tissue located therebetween; wherein movement of the control wire moves move the first and second clip arms between the open and closed configurations, application of a predetermined force to the control wire freeing the proximal end of the clip to move radially outward to engage an increased diameter portion of the capsule and disengage the control wire from the clip.
 12. The tissue clipping device of claim 11, wherein the capsule is configured to remain coupled to the clip when the control wire disengages from the clip.
 13. The tissue clipping device of claim 11, wherein the clip is a multi-piece clip.
 14. The tissue clipping device of claim 11, wherein a distal end of the control wire includes an enlargement configured to engage the clip.
 15. The tissue clipping device of claim 14, wherein the clip includes a recess having a shape corresponding to the shape of the enlargement of the control wire.
 16. The tissue clipping device of claim 11, wherein the capsule includes a cavity formed therein, the increased diameter portion extending along a wall of the cavity, wherein retraction of the clip into the capsule causes the proximal end of the clip to move into the increased diameter portion.
 17. The tissue clipping device of claim 11, wherein the capsule includes a proximal section and a distal section coupled to one another by a post extending from the distal section into a corresponding cavity formed in the proximal section.
 18. The tissue clipping device of claim 17, wherein the movement of the clip into the capsule causes the post to break, permitting the proximal end of the clip to expand into the increased diameter portion.
 19. The tissue clipping device of claim 11, wherein the first and second clip arms include increased width shoulders engaging a distal end of the capsule to prevent the first and second clips arms from being withdrawn into the capsule beyond a predetermined distance corresponding to a length of the shoulders.
 20. A method for causing hemostasis, comprising: inserting into a body a medical device comprising a clip having first and second clip arms, a capsule housing a portion of the clip therein and a control wire extending through the flexible insertion member from a proximal end to a distal end removably coupled to the clip; positioning the medical device at a desired deployment location; moving the control wire distally to cause the clip to move distally relative to the capsule, the movement causing the first and second clip arms radially outward to a tissue-receiving configuration; adjusting a position of the clip so that target tissue is received between the first and second clip arms; drawing the control wire proximally relative to the capsule to draw the clip into the capsule to receive the target tissue between the first and second clip arms in a tissue gripping configuration; and applying a proximal tensile force of at least a threshold level to the control wire to cause a proximal end of the clip to be received in an enlarged diameter portion of the capsule and separate a joint coupling the control wire to the clip. 